In software development and related fields, defects are tracked and analyzed in “bug tracking” or “task tracking” systems. When defects are entered into the system they are generally tracked and analyzed on such variables as, product version, platform, defect severity, and date entered. When defects are fixed, the defect tracking system is updated to change the status of the defect to resolved or closed. A short explanation or comment about the cause of the defect and the changes made to fix it are typically captured.
These defect tracking systems are independent of the source control system which contains the actual work product (such as software code source code, design documents etc.) in question. As a result there is no correlation between the actual changes made to fix the defect and the information recorded in the defect tracking system. This lack of correlation between the defect tracked in the defect tracking system and the physical changes made to the source work product in the source control system presents many problems including:                No ability to identify which source files or modules are most prone to defects.        No ability to track whether the quality of a given source file or module is improving or declining over time.        No ability to prioritize quality assurance resources to test the most error prone files and modules.        
Organizations spend billions of dollars per year on quality assurance to find defects before product shipment. In addition, the economic cost of defects which are not found and cause later product failures is also very significant. So the inability of organizations to identify which source modules are most defect prone is a big issue with very real economic impacts.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.